Commit Graph

2179 Commits

Author SHA1 Message Date
Jinjiang Tu
8ce41b0f9d mm: fix NULL pointer dereference in alloc_pages_bulk_noprof
We triggered a NULL pointer dereference for ac.preferred_zoneref->zone in
alloc_pages_bulk_noprof() when the task is migrated between cpusets.

When cpuset is enabled, in prepare_alloc_pages(), ac->nodemask may be
&current->mems_allowed.  when first_zones_zonelist() is called to find
preferred_zoneref, the ac->nodemask may be modified concurrently if the
task is migrated between different cpusets.  Assuming we have 2 NUMA Node,
when traversing Node1 in ac->zonelist, the nodemask is 2, and when
traversing Node2 in ac->zonelist, the nodemask is 1.  As a result, the
ac->preferred_zoneref points to NULL zone.

In alloc_pages_bulk_noprof(), for_each_zone_zonelist_nodemask() finds a
allowable zone and calls zonelist_node_idx(ac.preferred_zoneref), leading
to NULL pointer dereference.

__alloc_pages_noprof() fixes this issue by checking NULL pointer in commit
ea57485af8 ("mm, page_alloc: fix check for NULL preferred_zone") and
commit df76cee6bb ("mm, page_alloc: remove redundant checks from alloc
fastpath").

To fix it, check NULL pointer for preferred_zoneref->zone.

Link: https://lkml.kernel.org/r/20241113083235.166798-1-tujinjiang@huawei.com
Fixes: 387ba26fb1 ("mm/page_alloc: add a bulk page allocator")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-14 22:43:48 -08:00
Roman Gushchin
66edc3a589 mm: page_alloc: move mlocked flag clearance into free_pages_prepare()
Syzbot reported a bad page state problem caused by a page being freed
using free_page() still having a mlocked flag at free_pages_prepare()
stage:

  BUG: Bad page state in process syz.5.504  pfn:61f45
  page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61f45
  flags: 0xfff00000080204(referenced|workingset|mlocked|node=0|zone=1|lastcpupid=0x7ff)
  raw: 00fff00000080204 0000000000000000 dead000000000122 0000000000000000
  raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
  page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
  page_owner tracks the page as allocated
  page last allocated via order 0, migratetype Unmovable, gfp_mask 0x400dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO), pid 8443, tgid 8442 (syz.5.504), ts 201884660643, free_ts 201499827394
   set_page_owner include/linux/page_owner.h:32 [inline]
   post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537
   prep_new_page mm/page_alloc.c:1545 [inline]
   get_page_from_freelist+0x303f/0x3190 mm/page_alloc.c:3457
   __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4733
   alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
   kvm_coalesced_mmio_init+0x1f/0xf0 virt/kvm/coalesced_mmio.c:99
   kvm_create_vm virt/kvm/kvm_main.c:1235 [inline]
   kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5488 [inline]
   kvm_dev_ioctl+0x12dc/0x2240 virt/kvm/kvm_main.c:5530
   __do_compat_sys_ioctl fs/ioctl.c:1007 [inline]
   __se_compat_sys_ioctl+0x510/0xc90 fs/ioctl.c:950
   do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
   __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/common.c:386
   do_fast_syscall_32+0x34/0x80 arch/x86/entry/common.c:411
   entry_SYSENTER_compat_after_hwframe+0x84/0x8e
  page last free pid 8399 tgid 8399 stack trace:
   reset_page_owner include/linux/page_owner.h:25 [inline]
   free_pages_prepare mm/page_alloc.c:1108 [inline]
   free_unref_folios+0xf12/0x18d0 mm/page_alloc.c:2686
   folios_put_refs+0x76c/0x860 mm/swap.c:1007
   free_pages_and_swap_cache+0x5c8/0x690 mm/swap_state.c:335
   __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
   tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
   tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
   tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373
   tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465
   exit_mmap+0x496/0xc40 mm/mmap.c:1926
   __mmput+0x115/0x390 kernel/fork.c:1348
   exit_mm+0x220/0x310 kernel/exit.c:571
   do_exit+0x9b2/0x28e0 kernel/exit.c:926
   do_group_exit+0x207/0x2c0 kernel/exit.c:1088
   __do_sys_exit_group kernel/exit.c:1099 [inline]
   __se_sys_exit_group kernel/exit.c:1097 [inline]
   __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097
   x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232
   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
  Modules linked in:
  CPU: 0 UID: 0 PID: 8442 Comm: syz.5.504 Not tainted 6.12.0-rc6-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
  Call Trace:
   <TASK>
   __dump_stack lib/dump_stack.c:94 [inline]
   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
   bad_page+0x176/0x1d0 mm/page_alloc.c:501
   free_page_is_bad mm/page_alloc.c:918 [inline]
   free_pages_prepare mm/page_alloc.c:1100 [inline]
   free_unref_page+0xed0/0xf20 mm/page_alloc.c:2638
   kvm_destroy_vm virt/kvm/kvm_main.c:1327 [inline]
   kvm_put_kvm+0xc75/0x1350 virt/kvm/kvm_main.c:1386
   kvm_vcpu_release+0x54/0x60 virt/kvm/kvm_main.c:4143
   __fput+0x23f/0x880 fs/file_table.c:431
   task_work_run+0x24f/0x310 kernel/task_work.c:239
   exit_task_work include/linux/task_work.h:43 [inline]
   do_exit+0xa2f/0x28e0 kernel/exit.c:939
   do_group_exit+0x207/0x2c0 kernel/exit.c:1088
   __do_sys_exit_group kernel/exit.c:1099 [inline]
   __se_sys_exit_group kernel/exit.c:1097 [inline]
   __ia32_sys_exit_group+0x3f/0x40 kernel/exit.c:1097
   ia32_sys_call+0x2624/0x2630 arch/x86/include/generated/asm/syscalls_32.h:253
   do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
   __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/common.c:386
   do_fast_syscall_32+0x34/0x80 arch/x86/entry/common.c:411
   entry_SYSENTER_compat_after_hwframe+0x84/0x8e
  RIP: 0023:0xf745d579
  Code: Unable to access opcode bytes at 0xf745d54f.
  RSP: 002b:00000000f75afd6c EFLAGS: 00000206 ORIG_RAX: 00000000000000fc
  RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: 00000000ffffff9c RDI: 00000000f744cff4
  RBP: 00000000f717ae61 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
  R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
   </TASK>

The problem was originally introduced by commit b109b87050 ("mm/munlock:
replace clear_page_mlock() by final clearance"): it was focused on
handling pagecache and anonymous memory and wasn't suitable for lower
level get_page()/free_page() API's used for example by KVM, as with this
reproducer.

Fix it by moving the mlocked flag clearance down to free_page_prepare().

The bug itself if fairly old and harmless (aside from generating these
warnings), aside from a small memory leak - "bad" pages are stopped from
being allocated again.

Link: https://lkml.kernel.org/r/20241106195354.270757-1-roman.gushchin@linux.dev
Fixes: b109b87050 ("mm/munlock: replace clear_page_mlock() by final clearance")
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Reported-by: syzbot+e985d3026c4fd041578e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6729f475.050a0220.701a.0019.GAE@google.com
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-11 17:20:23 -08:00
Yu Zhao
c928807f6f mm/page_alloc: keep track of free highatomic
OOM kills due to vastly overestimated free highatomic reserves were
observed:

  ... invoked oom-killer: gfp_mask=0x100cca(GFP_HIGHUSER_MOVABLE), order=0 ...
  Node 0 Normal free:1482936kB boost:0kB min:410416kB low:739404kB high:1068392kB reserved_highatomic:1073152KB ...
  Node 0 Normal: 1292*4kB (ME) 1920*8kB (E) 383*16kB (UE) 220*32kB (ME) 340*64kB (E) 2155*128kB (UE) 3243*256kB (UE) 615*512kB (U) 1*1024kB (M) 0*2048kB 0*4096kB = 1477408kB

The second line above shows that the OOM kill was due to the following
condition:

  free (1482936kB) - reserved_highatomic (1073152kB) = 409784KB < min (410416kB)

And the third line shows there were no free pages in any
MIGRATE_HIGHATOMIC pageblocks, which otherwise would show up as type 'H'. 
Therefore __zone_watermark_unusable_free() underestimated the usable free
memory by over 1GB, which resulted in the unnecessary OOM kill above.

The comments in __zone_watermark_unusable_free() warns about the potential
risk, i.e.,

  If the caller does not have rights to reserves below the min
  watermark then subtract the high-atomic reserves. This will
  over-estimate the size of the atomic reserve but it avoids a search.

However, it is possible to keep track of free pages in reserved highatomic
pageblocks with a new per-zone counter nr_free_highatomic protected by the
zone lock, to avoid a search when calculating the usable free memory.  And
the cost would be minimal, i.e., simple arithmetics in the highatomic
alloc/free/move paths.

Note that since nr_free_highatomic can be relatively small, using a
per-cpu counter might cause too much drift and defeat its purpose, in
addition to the extra memory overhead.

Dependson e0932b6c1f ("mm: page_alloc: consolidate free page accounting") - see [1]

[akpm@linux-foundation.org: s/if/else if/, per Johannes, stealth whitespace tweak]
Link: https://lkml.kernel.org/r/20241028182653.3420139-1-yuzhao@google.com
Link: https://lkml.kernel.org/r/0d0ddb33-fcdc-43e2-801f-0c1df2031afb@suse.cz [1]
Fixes: 0aaa29a56e ("mm, page_alloc: reserve pageblocks for high-order atomic allocations on demand")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: Link Lin <linkl@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-07 14:14:58 -08:00
Hugh Dickins
f8f931bba0 mm/thp: fix deferred split unqueue naming and locking
Recent changes are putting more pressure on THP deferred split queues:
under load revealing long-standing races, causing list_del corruptions,
"Bad page state"s and worse (I keep BUGs in both of those, so usually
don't get to see how badly they end up without).  The relevant recent
changes being 6.8's mTHP, 6.10's mTHP swapout, and 6.12's mTHP swapin,
improved swap allocation, and underused THP splitting.

Before fixing locking: rename misleading folio_undo_large_rmappable(),
which does not undo large_rmappable, to folio_unqueue_deferred_split(),
which is what it does.  But that and its out-of-line __callee are mm
internals of very limited usability: add comment and WARN_ON_ONCEs to
check usage; and return a bool to say if a deferred split was unqueued,
which can then be used in WARN_ON_ONCEs around safety checks (sparing
callers the arcane conditionals in __folio_unqueue_deferred_split()).

Just omit the folio_unqueue_deferred_split() from free_unref_folios(), all
of whose callers now call it beforehand (and if any forget then bad_page()
will tell) - except for its caller put_pages_list(), which itself no
longer has any callers (and will be deleted separately).

Swapout: mem_cgroup_swapout() has been resetting folio->memcg_data 0
without checking and unqueueing a THP folio from deferred split list;
which is unfortunate, since the split_queue_lock depends on the memcg
(when memcg is enabled); so swapout has been unqueueing such THPs later,
when freeing the folio, using the pgdat's lock instead: potentially
corrupting the memcg's list.  __remove_mapping() has frozen refcount to 0
here, so no problem with calling folio_unqueue_deferred_split() before
resetting memcg_data.

That goes back to 5.4 commit 87eaceb3fa ("mm: thp: make deferred split
shrinker memcg aware"): which included a check on swapcache before adding
to deferred queue, but no check on deferred queue before adding THP to
swapcache.  That worked fine with the usual sequence of events in reclaim
(though there were a couple of rare ways in which a THP on deferred queue
could have been swapped out), but 6.12 commit dafff3f4c8 ("mm: split
underused THPs") avoids splitting underused THPs in reclaim, which makes
swapcache THPs on deferred queue commonplace.

Keep the check on swapcache before adding to deferred queue?  Yes: it is
no longer essential, but preserves the existing behaviour, and is likely
to be a worthwhile optimization (vmstat showed much more traffic on the
queue under swapping load if the check was removed); update its comment.

Memcg-v1 move (deprecated): mem_cgroup_move_account() has been changing
folio->memcg_data without checking and unqueueing a THP folio from the
deferred list, sometimes corrupting "from" memcg's list, like swapout. 
Refcount is non-zero here, so folio_unqueue_deferred_split() can only be
used in a WARN_ON_ONCE to validate the fix, which must be done earlier:
mem_cgroup_move_charge_pte_range() first try to split the THP (splitting
of course unqueues), or skip it if that fails.  Not ideal, but moving
charge has been requested, and khugepaged should repair the THP later:
nobody wants new custom unqueueing code just for this deprecated case.

The 87eaceb3fa commit did have the code to move from one deferred list
to another (but was not conscious of its unsafety while refcount non-0);
but that was removed by 5.6 commit fac0516b55 ("mm: thp: don't need care
deferred split queue in memcg charge move path"), which argued that the
existence of a PMD mapping guarantees that the THP cannot be on a deferred
list.  As above, false in rare cases, and now commonly false.

Backport to 6.11 should be straightforward.  Earlier backports must take
care that other _deferred_list fixes and dependencies are included.  There
is not a strong case for backports, but they can fix cornercases.

Link: https://lkml.kernel.org/r/8dc111ae-f6db-2da7-b25c-7a20b1effe3b@google.com
Fixes: 87eaceb3fa ("mm: thp: make deferred split shrinker memcg aware")
Fixes: dafff3f4c8 ("mm: split underused THPs")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-05 16:49:54 -08:00
Hugh Dickins
e66f3185fa mm/thp: fix deferred split queue not partially_mapped
Recent changes are putting more pressure on THP deferred split queues:
under load revealing long-standing races, causing list_del corruptions,
"Bad page state"s and worse (I keep BUGs in both of those, so usually
don't get to see how badly they end up without).  The relevant recent
changes being 6.8's mTHP, 6.10's mTHP swapout, and 6.12's mTHP swapin,
improved swap allocation, and underused THP splitting.

The new unlocked list_del_init() in deferred_split_scan() is buggy.  I
gave bad advice, it looks plausible since that's a local on-stack list,
but the fact is that it can race with a third party freeing or migrating
the preceding folio (properly unqueueing it with refcount 0 while holding
split_queue_lock), thereby corrupting the list linkage.

The obvious answer would be to take split_queue_lock there: but it has a
long history of contention, so I'm reluctant to add to that.  Instead,
make sure that there is always one safe (raised refcount) folio before, by
delaying its folio_put().  (And of course I was wrong to suggest updating
split_queue_len without the lock: leave that until the splice.)

And remove two over-eager partially_mapped checks, restoring those tests
to how they were before: if uncharge_folio() or free_tail_page_prepare()
finds _deferred_list non-empty, it's in trouble whether or not that folio
is partially_mapped (and the flag was already cleared in the latter case).

Link: https://lkml.kernel.org/r/81e34a8b-113a-0701-740e-2135c97eb1d7@google.com
Fixes: dafff3f4c8 ("mm: split underused THPs")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Usama Arif <usamaarif642@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-05 16:49:54 -08:00
Matt Fleming
281dd25c1a mm/page_alloc: let GFP_ATOMIC order-0 allocs access highatomic reserves
Under memory pressure it's possible for GFP_ATOMIC order-0 allocations to
fail even though free pages are available in the highatomic reserves. 
GFP_ATOMIC allocations cannot trigger unreserve_highatomic_pageblock()
since it's only run from reclaim.

Given that such allocations will pass the watermarks in
__zone_watermark_unusable_free(), it makes sense to fallback to highatomic
reserves the same way that ALLOC_OOM can.

This fixes order-0 page allocation failures observed on Cloudflare's fleet
when handling network packets:

  kswapd1: page allocation failure: order:0, mode:0x820(GFP_ATOMIC),
  nodemask=(null),cpuset=/,mems_allowed=0-7
  CPU: 10 PID: 696 Comm: kswapd1 Kdump: loaded Tainted: G           O 6.6.43-CUSTOM #1
  Hardware name: MACHINE
  Call Trace:
   <IRQ>
   dump_stack_lvl+0x3c/0x50
   warn_alloc+0x13a/0x1c0
   __alloc_pages_slowpath.constprop.0+0xc9d/0xd10
   __alloc_pages+0x327/0x340
   __napi_alloc_skb+0x16d/0x1f0
   bnxt_rx_page_skb+0x96/0x1b0 [bnxt_en]
   bnxt_rx_pkt+0x201/0x15e0 [bnxt_en]
   __bnxt_poll_work+0x156/0x2b0 [bnxt_en]
   bnxt_poll+0xd9/0x1c0 [bnxt_en]
   __napi_poll+0x2b/0x1b0
   bpf_trampoline_6442524138+0x7d/0x1000
   __napi_poll+0x5/0x1b0
   net_rx_action+0x342/0x740
   handle_softirqs+0xcf/0x2b0
   irq_exit_rcu+0x6c/0x90
   sysvec_apic_timer_interrupt+0x72/0x90
   </IRQ>

[mfleming@cloudflare.com: update comment]
  Link: https://lkml.kernel.org/r/20241015125158.3597702-1-matt@readmodwrite.com
Link: https://lkml.kernel.org/r/20241011120737.3300370-1-matt@readmodwrite.com
Link: https://lore.kernel.org/all/CAGis_TWzSu=P7QJmjD58WWiu3zjMTVKSzdOwWE8ORaGytzWJwQ@mail.gmail.com/
Fixes: 1d91df85f3 ("mm/page_alloc: handle a missing case for memalloc_nocma_{save/restore} APIs")
Signed-off-by: Matt Fleming <mfleming@cloudflare.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28 21:40:39 -07:00
Linus Torvalds
617a814f14 ALong with the usual shower of singleton patches, notable patch series in
this pull request are:
 
 "Align kvrealloc() with krealloc()" from Danilo Krummrich.  Adds
 consistency to the APIs and behaviour of these two core allocation
 functions.  This also simplifies/enables Rustification.
 
 "Some cleanups for shmem" from Baolin Wang.  No functional changes - mode
 code reuse, better function naming, logic simplifications.
 
 "mm: some small page fault cleanups" from Josef Bacik.  No functional
 changes - code cleanups only.
 
 "Various memory tiering fixes" from Zi Yan.  A small fix and a little
 cleanup.
 
 "mm/swap: remove boilerplate" from Yu Zhao.  Code cleanups and
 simplifications and .text shrinkage.
 
 "Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt.  This
 is a feature, it adds new feilds to /proc/vmstat such as
 
     $ grep kstack /proc/vmstat
     kstack_1k 3
     kstack_2k 188
     kstack_4k 11391
     kstack_8k 243
     kstack_16k 0
 
 which tells us that 11391 processes used 4k of stack while none at all
 used 16k.  Useful for some system tuning things, but partivularly useful
 for "the dynamic kernel stack project".
 
 "kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov.
 Teaches kmemleak to detect leaksage of percpu memory.
 
 "mm: memcg: page counters optimizations" from Roman Gushchin.  "3
 independent small optimizations of page counters".
 
 "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David
 Hildenbrand.  Improves PTE/PMD splitlock detection, makes powerpc/8xx work
 correctly by design rather than by accident.
 
 "mm: remove arch_make_page_accessible()" from David Hildenbrand.  Some
 folio conversions which make arch_make_page_accessible() unneeded.
 
 "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel.
 Cleans up and fixes our handling of the resetting of the cgroup/process
 peak-memory-use detector.
 
 "Make core VMA operations internal and testable" from Lorenzo Stoakes.
 Rationalizaion and encapsulation of the VMA manipulation APIs.  With a
 view to better enable testing of the VMA functions, even from a
 userspace-only harness.
 
 "mm: zswap: fixes for global shrinker" from Takero Funaki.  Fix issues in
 the zswap global shrinker, resulting in improved performance.
 
 "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao.  Fill in
 some missing info in /proc/zoneinfo.
 
 "mm: replace follow_page() by folio_walk" from David Hildenbrand.  Code
 cleanups and rationalizations (conversion to folio_walk()) resulting in
 the removal of follow_page().
 
 "improving dynamic zswap shrinker protection scheme" from Nhat Pham.  Some
 tuning to improve zswap's dynamic shrinker.  Significant reductions in
 swapin and improvements in performance are shown.
 
 "mm: Fix several issues with unaccepted memory" from Kirill Shutemov.
 Improvements to the new unaccepted memory feature,
 
 "mm/mprotect: Fix dax puds" from Peter Xu.  Implements mprotect on DAX
 PUDs.  This was missing, although nobody seems to have notied yet.
 
 "Introduce a store type enum for the Maple tree" from Sidhartha Kumar.
 Cleanups and modest performance improvements for the maple tree library
 code.
 
 "memcg: further decouple v1 code from v2" from Shakeel Butt.  Move more
 cgroup v1 remnants away from the v2 memcg code.
 
 "memcg: initiate deprecation of v1 features" from Shakeel Butt.  Adds
 various warnings telling users that memcg v1 features are deprecated.
 
 "mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li.
 Greatly improves the success rate of the mTHP swap allocation.
 
 "mm: introduce numa_memblks" from Mike Rapoport.  Moves various disparate
 per-arch implementations of numa_memblk code into generic code.
 
 "mm: batch free swaps for zap_pte_range()" from Barry Song.  Greatly
 improves the performance of munmap() of swap-filled ptes.
 
 "support large folio swap-out and swap-in for shmem" from Baolin Wang.
 With this series we no longer split shmem large folios into simgle-page
 folios when swapping out shmem.
 
 "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao.  Nice performance
 improvements and code reductions for gigantic folios.
 
 "support shmem mTHP collapse" from Baolin Wang.  Adds support for
 khugepaged's collapsing of shmem mTHP folios.
 
 "mm: Optimize mseal checks" from Pedro Falcato.  Fixes an mprotect()
 performance regression due to the addition of mseal().
 
 "Increase the number of bits available in page_type" from Matthew Wilcox.
 Increases the number of bits available in page_type!
 
 "Simplify the page flags a little" from Matthew Wilcox.  Many legacy page
 flags are now folio flags, so the page-based flags and their
 accessors/mutators can be removed.
 
 "mm: store zero pages to be swapped out in a bitmap" from Usama Arif.  An
 optimization which permits us to avoid writing/reading zero-filled zswap
 pages to backing store.
 
 "Avoid MAP_FIXED gap exposure" from Liam Howlett.  Fixes a race window
 which occurs when a MAP_FIXED operqtion is occurring during an unrelated
 vma tree walk.
 
 "mm: remove vma_merge()" from Lorenzo Stoakes.  Major rotorooting of the
 vma_merge() functionality, making ot cleaner, more testable and better
 tested.
 
 "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.  Minor
 fixups of DAMON selftests and kunit tests.
 
 "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.  Code
 cleanups and folio conversions.
 
 "Shmem mTHP controls and stats improvements" from Ryan Roberts.  Cleanups
 for shmem controls and stats.
 
 "mm: count the number of anonymous THPs per size" from Barry Song.  Expose
 additional anon THP stats to userspace for improved tuning.
 
 "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio
 conversions and removal of now-unused page-based APIs.
 
 "replace per-quota region priorities histogram buffer with per-context
 one" from SeongJae Park.  DAMON histogram rationalization.
 
 "Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae
 Park.  DAMON documentation updates.
 
 "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve
 related doc and warn" from Jason Wang: fixes usage of page allocator
 __GFP_NOFAIL and GFP_ATOMIC flags.
 
 "mm: split underused THPs" from Yu Zhao.  Improve THP=always policy - this
 was overprovisioning THPs in sparsely accessed memory areas.
 
 "zram: introduce custom comp backends API" frm Sergey Senozhatsky.  Add
 support for zram run-time compression algorithm tuning.
 
 "mm: Care about shadow stack guard gap when getting an unmapped area" from
 Mark Brown.  Fix up the various arch_get_unmapped_area() implementations
 to better respect guard areas.
 
 "Improve mem_cgroup_iter()" from Kinsey Ho.  Improve the reliability of
 mem_cgroup_iter() and various code cleanups.
 
 "mm: Support huge pfnmaps" from Peter Xu.  Extends the usage of huge
 pfnmap support.
 
 "resource: Fix region_intersects() vs add_memory_driver_managed()" from
 Huang Ying.  Fix a bug in region_intersects() for systems with CXL memory.
 
 "mm: hwpoison: two more poison recovery" from Kefeng Wang.  Teaches a
 couple more code paths to correctly recover from the encountering of
 poisoned memry.
 
 "mm: enable large folios swap-in support" from Barry Song.  Support the
 swapin of mTHP memory into appropriately-sized folios, rather than into
 single-page folios.
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Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Along with the usual shower of singleton patches, notable patch series
  in this pull request are:

   - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
     consistency to the APIs and behaviour of these two core allocation
     functions. This also simplifies/enables Rustification.

   - "Some cleanups for shmem" from Baolin Wang. No functional changes -
     mode code reuse, better function naming, logic simplifications.

   - "mm: some small page fault cleanups" from Josef Bacik. No
     functional changes - code cleanups only.

   - "Various memory tiering fixes" from Zi Yan. A small fix and a
     little cleanup.

   - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
     simplifications and .text shrinkage.

   - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
     Butt. This is a feature, it adds new feilds to /proc/vmstat such as

       $ grep kstack /proc/vmstat
       kstack_1k 3
       kstack_2k 188
       kstack_4k 11391
       kstack_8k 243
       kstack_16k 0

     which tells us that 11391 processes used 4k of stack while none at
     all used 16k. Useful for some system tuning things, but
     partivularly useful for "the dynamic kernel stack project".

   - "kmemleak: support for percpu memory leak detect" from Pavel
     Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.

   - "mm: memcg: page counters optimizations" from Roman Gushchin. "3
     independent small optimizations of page counters".

   - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
     David Hildenbrand. Improves PTE/PMD splitlock detection, makes
     powerpc/8xx work correctly by design rather than by accident.

   - "mm: remove arch_make_page_accessible()" from David Hildenbrand.
     Some folio conversions which make arch_make_page_accessible()
     unneeded.

   - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
     Finkel. Cleans up and fixes our handling of the resetting of the
     cgroup/process peak-memory-use detector.

   - "Make core VMA operations internal and testable" from Lorenzo
     Stoakes. Rationalizaion and encapsulation of the VMA manipulation
     APIs. With a view to better enable testing of the VMA functions,
     even from a userspace-only harness.

   - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
     issues in the zswap global shrinker, resulting in improved
     performance.

   - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
     in some missing info in /proc/zoneinfo.

   - "mm: replace follow_page() by folio_walk" from David Hildenbrand.
     Code cleanups and rationalizations (conversion to folio_walk())
     resulting in the removal of follow_page().

   - "improving dynamic zswap shrinker protection scheme" from Nhat
     Pham. Some tuning to improve zswap's dynamic shrinker. Significant
     reductions in swapin and improvements in performance are shown.

   - "mm: Fix several issues with unaccepted memory" from Kirill
     Shutemov. Improvements to the new unaccepted memory feature,

   - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
     DAX PUDs. This was missing, although nobody seems to have notied
     yet.

   - "Introduce a store type enum for the Maple tree" from Sidhartha
     Kumar. Cleanups and modest performance improvements for the maple
     tree library code.

   - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
     more cgroup v1 remnants away from the v2 memcg code.

   - "memcg: initiate deprecation of v1 features" from Shakeel Butt.
     Adds various warnings telling users that memcg v1 features are
     deprecated.

   - "mm: swap: mTHP swap allocator base on swap cluster order" from
     Chris Li. Greatly improves the success rate of the mTHP swap
     allocation.

   - "mm: introduce numa_memblks" from Mike Rapoport. Moves various
     disparate per-arch implementations of numa_memblk code into generic
     code.

   - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
     improves the performance of munmap() of swap-filled ptes.

   - "support large folio swap-out and swap-in for shmem" from Baolin
     Wang. With this series we no longer split shmem large folios into
     simgle-page folios when swapping out shmem.

   - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
     performance improvements and code reductions for gigantic folios.

   - "support shmem mTHP collapse" from Baolin Wang. Adds support for
     khugepaged's collapsing of shmem mTHP folios.

   - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
     performance regression due to the addition of mseal().

   - "Increase the number of bits available in page_type" from Matthew
     Wilcox. Increases the number of bits available in page_type!

   - "Simplify the page flags a little" from Matthew Wilcox. Many legacy
     page flags are now folio flags, so the page-based flags and their
     accessors/mutators can be removed.

   - "mm: store zero pages to be swapped out in a bitmap" from Usama
     Arif. An optimization which permits us to avoid writing/reading
     zero-filled zswap pages to backing store.

   - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
     window which occurs when a MAP_FIXED operqtion is occurring during
     an unrelated vma tree walk.

   - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
     the vma_merge() functionality, making ot cleaner, more testable and
     better tested.

   - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
     Minor fixups of DAMON selftests and kunit tests.

   - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
     Code cleanups and folio conversions.

   - "Shmem mTHP controls and stats improvements" from Ryan Roberts.
     Cleanups for shmem controls and stats.

   - "mm: count the number of anonymous THPs per size" from Barry Song.
     Expose additional anon THP stats to userspace for improved tuning.

   - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
     folio conversions and removal of now-unused page-based APIs.

   - "replace per-quota region priorities histogram buffer with
     per-context one" from SeongJae Park. DAMON histogram
     rationalization.

   - "Docs/damon: update GitHub repo URLs and maintainer-profile" from
     SeongJae Park. DAMON documentation updates.

   - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
     improve related doc and warn" from Jason Wang: fixes usage of page
     allocator __GFP_NOFAIL and GFP_ATOMIC flags.

   - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
     This was overprovisioning THPs in sparsely accessed memory areas.

   - "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
     Add support for zram run-time compression algorithm tuning.

   - "mm: Care about shadow stack guard gap when getting an unmapped
     area" from Mark Brown. Fix up the various arch_get_unmapped_area()
     implementations to better respect guard areas.

   - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
     of mem_cgroup_iter() and various code cleanups.

   - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
     pfnmap support.

   - "resource: Fix region_intersects() vs add_memory_driver_managed()"
     from Huang Ying. Fix a bug in region_intersects() for systems with
     CXL memory.

   - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
     a couple more code paths to correctly recover from the encountering
     of poisoned memry.

   - "mm: enable large folios swap-in support" from Barry Song. Support
     the swapin of mTHP memory into appropriately-sized folios, rather
     than into single-page folios"

* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
  zram: free secondary algorithms names
  uprobes: turn xol_area->pages[2] into xol_area->page
  uprobes: introduce the global struct vm_special_mapping xol_mapping
  Revert "uprobes: use vm_special_mapping close() functionality"
  mm: support large folios swap-in for sync io devices
  mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
  mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
  mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
  set_memory: add __must_check to generic stubs
  mm/vma: return the exact errno in vms_gather_munmap_vmas()
  memcg: cleanup with !CONFIG_MEMCG_V1
  mm/show_mem.c: report alloc tags in human readable units
  mm: support poison recovery from copy_present_page()
  mm: support poison recovery from do_cow_fault()
  resource, kunit: add test case for region_intersects()
  resource: make alloc_free_mem_region() works for iomem_resource
  mm: z3fold: deprecate CONFIG_Z3FOLD
  vfio/pci: implement huge_fault support
  mm/arm64: support large pfn mappings
  mm/x86: support large pfn mappings
  ...
2024-09-21 07:29:05 -07:00
Linus Torvalds
2004cef11e In the v6.12 scheduler development cycle we had 63 commits from 18 contributors:
- Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot de Oliveira's
    last major contribution to the kernel:
 
      "SCHED_DEADLINE servers can help fixing starvation issues of low priority
      tasks (e.g., SCHED_OTHER) when higher priority tasks monopolize CPU
      cycles. Today we have RT Throttling; DEADLINE servers should be able to
      replace and improve that."
 
      (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes,
       Youssef Esmat, Huang Shijie)
 
  - Preparatory changes for sched_ext integration:
 
      - Use set_next_task(.first) where required
      - Fix up set_next_task() implementations
      - Clean up DL server vs. core sched
      - Split up put_prev_task_balance()
      - Rework pick_next_task()
      - Combine the last put_prev_task() and the first set_next_task()
      - Rework dl_server
      - Add put_prev_task(.next)
 
       (Peter Zijlstra, with a fix by Tejun Heo)
 
  - Complete the EEVDF transition and refine EEVDF scheduling:
 
      - Implement delayed dequeue
      - Allow shorter slices to wakeup-preempt
      - Use sched_attr::sched_runtime to set request/slice suggestion
      - Document the new feature flags
      - Remove unused and duplicate-functionality fields
      - Simplify & unify pick_next_task_fair()
      - Misc debuggability enhancements
 
       (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann,
        Valentin Schneider and Chuyi Zhou)
 
  - Initialize the vruntime of a new task when it is first enqueued,
    resulting in significant decrease in latency of newly woken tasks.
    (Zhang Qiao)
 
  - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
    (K Prateek Nayak, Peter Zijlstra)
 
  - Clean up and clarify the usage of Clean up usage of rt_task()
    (Qais Yousef)
 
  - Preempt SCHED_IDLE entities in strict cgroup hierarchies
    (Tianchen Ding)
 
  - Clarify the documentation of time units for deadline scheduler
    parameters. (Christian Loehle)
 
  - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
    the original change seems to be working fine.
    (Phil Auld)
 
  - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
    Peilin He, Qais Yousefm and Vincent Guittot)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot
   de Oliveira's last major contribution to the kernel:

     "SCHED_DEADLINE servers can help fixing starvation issues of low
      priority tasks (e.g., SCHED_OTHER) when higher priority tasks
      monopolize CPU cycles. Today we have RT Throttling; DEADLINE
      servers should be able to replace and improve that."

   (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes, Youssef
   Esmat, Huang Shijie)

 - Preparatory changes for sched_ext integration:
     - Use set_next_task(.first) where required
     - Fix up set_next_task() implementations
     - Clean up DL server vs. core sched
     - Split up put_prev_task_balance()
     - Rework pick_next_task()
     - Combine the last put_prev_task() and the first set_next_task()
     - Rework dl_server
     - Add put_prev_task(.next)

   (Peter Zijlstra, with a fix by Tejun Heo)

 - Complete the EEVDF transition and refine EEVDF scheduling:
     - Implement delayed dequeue
     - Allow shorter slices to wakeup-preempt
     - Use sched_attr::sched_runtime to set request/slice suggestion
     - Document the new feature flags
     - Remove unused and duplicate-functionality fields
     - Simplify & unify pick_next_task_fair()
     - Misc debuggability enhancements

   (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann, Valentin
   Schneider and Chuyi Zhou)

 - Initialize the vruntime of a new task when it is first enqueued,
   resulting in significant decrease in latency of newly woken tasks
   (Zhang Qiao)

 - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
   (K Prateek Nayak, Peter Zijlstra)

 - Clean up and clarify the usage of Clean up usage of rt_task()
   (Qais Yousef)

 - Preempt SCHED_IDLE entities in strict cgroup hierarchies
   (Tianchen Ding)

 - Clarify the documentation of time units for deadline scheduler
   parameters (Christian Loehle)

 - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
   the original change seems to be working fine (Phil Auld)

 - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
   Peilin He, Qais Yousefm and Vincent Guittot)

* tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  sched/cpufreq: Use NSEC_PER_MSEC for deadline task
  cpufreq/cppc: Use NSEC_PER_MSEC for deadline task
  sched/deadline: Clarify nanoseconds in uapi
  sched/deadline: Convert schedtool example to chrt
  sched/debug: Fix the runnable tasks output
  sched: Fix sched_delayed vs sched_core
  kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
  kthread: Fix task state in kthread worker if being frozen
  sched/pelt: Use rq_clock_task() for hw_pressure
  sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
  sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
  sched: Add put_prev_task(.next)
  sched: Rework dl_server
  sched: Combine the last put_prev_task() and the first set_next_task()
  sched: Rework pick_next_task()
  sched: Split up put_prev_task_balance()
  sched: Clean up DL server vs core sched
  sched: Fixup set_next_task() implementations
  sched: Use set_next_task(.first) where required
  sched/fair: Properly deactivate sched_delayed task upon class change
  ...
2024-09-19 15:55:58 +02:00
Yu Zhao
95599ef684 mm/codetag: fix pgalloc_tag_split()
The current assumption is that a large folio can only be split into
order-0 folios.  That is not the case for hugeTLB demotion, nor for THP
split: see commit c010d47f10 ("mm: thp: split huge page to any lower
order pages").

When a large folio is split into ones of a lower non-zero order, only the
new head pages should be tagged.  Tagging tail pages can cause imbalanced
"calls" counters, since only head pages are untagged by pgalloc_tag_sub()
and the "calls" counts on tail pages are leaked, e.g.,

  # echo 2048kB >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote_size
  # echo 700 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
  # time echo 700 >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote
  # echo 0 >/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
  # grep alloc_gigantic_folio /proc/allocinfo

Before this patch:
  0  549427200  mm/hugetlb.c:1549 func:alloc_gigantic_folio

  real  0m2.057s
  user  0m0.000s
  sys   0m2.051s

After this patch:
  0          0  mm/hugetlb.c:1549 func:alloc_gigantic_folio

  real  0m1.711s
  user  0m0.000s
  sys   0m1.704s

Not tagging tail pages also improves the splitting time, e.g., by about
15% when demoting 1GB hugeTLB folios to 2MB ones, as shown above.

Link: https://lkml.kernel.org/r/20240906042108.1150526-2-yuzhao@google.com
Fixes: be25d1d4e8 ("mm: create new codetag references during page splitting")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:39:18 -07:00
Andrew Morton
6e94da943b mm/page_alloc: fix build with CONFIG_UNACCEPTED_MEMORY=n
When has_unaccepted_memory() is unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:

mm/page_alloc.c:7036:20: error: unused function 'has_unaccepted_memory' [-Werror,-Wunused-function]
7036 | static inline bool has_unaccepted_memory(void)
|                    ^~~~~~~~~~~~~~~~~~~~~

Fix it by removeing the CONFIG_UNACCEPTED_MEMORY=n stub.

Link: https://lkml.kernel.org/r/20240905142220.49d93337a0abce5690e515d9@linux-foundation.org
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Closes: https://lkml.kernel.org/r/20240905171553.275054-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:39:15 -07:00
Yosry Ahmed
ec867977fe mm: page_alloc: fix missed updates of PGFREE in free_unref_{page/folios}
PGFREE is currently updated in two code paths:

- __free_pages_ok(): for pages freed to the buddy allocator.
- free_unref_page_commit(): for pages freed to the pcplists.

Before commit df1acc8569 ("mm/page_alloc: avoid conflating IRQs disabled
with zone->lock"), free_unref_page_commit() used to fallback to freeing
isolated pages directly to the buddy allocator through free_one_page(). 
This was done _after_ updating PGFREE, so the counter was correctly
updated.

However, that commit moved the fallback logic to its callers (now called
free_unref_page() and free_unref_folios()), so PGFREE was no longer
updated in this fallback case.

Now that the code has developed, there are more cases in free_unref_page()
and free_unref_folios() where we fallback to calling free_one_page() (e.g.
!pcp_allowed_order(), pcp_spin_trylock() fails).  These cases also miss
updating PGFREE.

To make sure PGFREE is updated in all cases where pages are freed to the
buddy allocator, move the update down the stack to free_one_page().

This was noticed through code inspection, although it should be noticeable
at runtime (at least with some workloads).

Link: https://lkml.kernel.org/r/20240904205419.821776-1-yosryahmed@google.com
Fixes: df1acc8569 ("mm/page_alloc: avoid conflating IRQs disabled with zone->lock")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:39:14 -07:00
Huan Yang
94deaf69dc mm: page_alloc: simpify page del and expand
When page del from buddy and need expand, it will account free_pages in
zone's migratetype.

The current way is to subtract the page number of the current order when
deleting, and then add it back when expanding.

This is unnecessary, as when migrating the same type, we can directly
record the difference between the high-order pages and the expand added,
and then subtract it directly.

This patch merge that, only when del and expand done, then account
free_pages.

Link: https://lkml.kernel.org/r/20240826064048.187790-1-link@vivo.com
Signed-off-by: Huan Yang <link@vivo.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:39:05 -07:00
Usama Arif
8422acdc97 mm: introduce a pageflag for partially mapped folios
Currently folio->_deferred_list is used to keep track of partially_mapped
folios that are going to be split under memory pressure.  In the next
patch, all THPs that are faulted in and collapsed by khugepaged are also
going to be tracked using _deferred_list.

This patch introduces a pageflag to be able to distinguish between
partially mapped folios and others in the deferred_list at split time in
deferred_split_scan.  Its needed as __folio_remove_rmap decrements
_mapcount, _large_mapcount and _entire_mapcount, hence it won't be
possible to distinguish between partially mapped folios and others in
deferred_split_scan.

Eventhough it introduces an extra flag to track if the folio is partially
mapped, there is no functional change intended with this patch and the
flag is not useful in this patch itself, it will become useful in the next
patch when _deferred_list has non partially mapped folios.

Link: https://lkml.kernel.org/r/20240830100438.3623486-5-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:39:04 -07:00
Barry Song
903edea6c5 mm: warn about illegal __GFP_NOFAIL usage in a more appropriate location and manner
Three points for this change:

1. We should consolidate all warnings in one place. Currently, the
   order > 1 warning is in the hotpath, while others are in less
   likely scenarios. Moving all warnings to the slowpath will reduce
   the overhead for order > 1 and increase the visibility of other
   warnings.

2. We currently have two warnings for order: one for order > 1 in
   the hotpath and another for order > costly_order in the laziest
   path. I suggest standardizing on order > 1 since it's been in
   use for a long time.

3. We don't need to check for __GFP_NOWARN in this case. __GFP_NOWARN
   is meant to suppress allocation failure reports, but here we're
   dealing with bug detection, not allocation failures. So replace
   WARN_ON_ONCE_GFP by WARN_ON_ONCE.

[v-songbaohua@oppo.com: also update the doc for __GFP_NOFAIL with order > 1]
  Link: https://lkml.kernel.org/r/20240903223935.1697-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240830202823.21478-4-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eugenio Pérez" <eperezma@redhat.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Xie Yongji <xieyongji@bytedance.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:39:03 -07:00
Barry Song
5d65c8d758 mm: count the number of anonymous THPs per size
Patch series "mm: count the number of anonymous THPs per size", v4.

Knowing the number of transparent anon THPs in the system is crucial
for performance analysis. It helps in understanding the ratio and
distribution of THPs versus small folios throughout the system.

Additionally, partial unmapping by userspace can lead to significant waste
of THPs over time and increase memory reclamation pressure. We need this
information for comprehensive system tuning.


This patch (of 2):

Let's track for each anonymous THP size, how many of them are currently
allocated.  We'll track the complete lifespan of an anon THP, starting
when it becomes an anon THP ("large anon folio") (->mapping gets set),
until it gets freed (->mapping gets cleared).

Introduce a new "nr_anon" counter per THP size and adjust the
corresponding counter in the following cases:
* We allocate a new THP and call folio_add_new_anon_rmap() to map
   it the first time and turn it into an anon THP.
* We split an anon THP into multiple smaller ones.
* We migrate an anon THP, when we prepare the destination.
* We free an anon THP back to the buddy.

Note that AnonPages in /proc/meminfo currently tracks the total number of
*mapped* anonymous *pages*, and therefore has slightly different
semantics.  In the future, we might also want to track "nr_anon_mapped"
for each THP size, which might be helpful when comparing it to the number
of allocated anon THPs (long-term pinning, stuck in swapcache, memory
leaks, ...).

Further note that for now, we only track anon THPs after they got their
->mapping set, for example via folio_add_new_anon_rmap().  If we would
allocate some in the swapcache, they will only show up in the statistics
for now after they have been mapped to user space the first time, where we
call folio_add_new_anon_rmap().

[akpm@linux-foundation.org: documentation fixups, per David]
  Link: https://lkml.kernel.org/r/3e8add35-e26b-443b-8a04-1078f4bc78f6@redhat.com
Link: https://lkml.kernel.org/r/20240824010441.21308-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240824010441.21308-2-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuai Yuan <yuanshuai@oppo.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:38:57 -07:00
Zhongkun He
435b3894e7 mm:page_alloc: fix the NULL ac->nodemask in __alloc_pages_slowpath()
should_reclaim_retry() is not ALLOC_CPUSET aware and that means that it
considers reclaimability of NUMA nodes which are outside of the cpuset. 
If other nodes have a lot of reclaimable memory then should_reclaim_retry
would instruct page allocator to retry even though there is no memory
reclaimable on the cpuset nodemask.  This is not really a huge problem
because the number of retries without any reclaim progress is bound but it
could be certainly improved.  This is a cold path so this shouldn't really
have a measurable impact on performance on most workloads.

1.Test step and the machines.
------------
root@vm:/sys/fs/cgroup/test# numactl -H | grep size
node 0 size: 9477 MB
node 1 size: 10079 MB
node 2 size: 10079 MB
node 3 size: 10078 MB

root@vm:/sys/fs/cgroup/test# cat cpuset.mems
    2

root@vm:/sys/fs/cgroup/test# stress --vm 1 --vm-bytes 12g  --vm-keep
stress: info: [33430] dispatching hogs: 0 cpu, 0 io, 1 vm, 0 hdd
stress: FAIL: [33430] (425) <-- worker 33431 got signal 9
stress: WARN: [33430] (427) now reaping child worker processes
stress: FAIL: [33430] (461) failed run completed in 2s

2. reclaim_retry_zone info:

We can only alloc pages from node=2, but the reclaim_retry_zone is
node=0 and return true.

root@vm:/sys/kernel/debug/tracing# cat trace
stress-33431   [001] ..... 13223.617311: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=1 wmark_check=1
stress-33431   [001] ..... 13223.617682: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=2 wmark_check=1
stress-33431   [001] ..... 13223.618103: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=3 wmark_check=1
stress-33431   [001] ..... 13223.618454: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=4 wmark_check=1
stress-33431   [001] ..... 13223.618770: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=5 wmark_check=1
stress-33431   [001] ..... 13223.619150: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=6 wmark_check=1
stress-33431   [001] ..... 13223.619510: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=7 wmark_check=1
stress-33431   [001] ..... 13223.619850: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=8 wmark_check=1
stress-33431   [001] ..... 13223.620171: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=9 wmark_check=1
stress-33431   [001] ..... 13223.620533: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=10 wmark_check=1
stress-33431   [001] ..... 13223.620894: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=11 wmark_check=1
stress-33431   [001] ..... 13223.621224: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=12 wmark_check=1
stress-33431   [001] ..... 13223.621551: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=13 wmark_check=1
stress-33431   [001] ..... 13223.621847: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=14 wmark_check=1
stress-33431   [001] ..... 13223.622200: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=15 wmark_check=1
stress-33431   [001] ..... 13223.622580: reclaim_retry_zone: node=0 zone=Normal   order=0 reclaimable=4260 available=1772019 min_wmark=5962 no_progress_loops=16 wmark_check=1

With this patch, we can check the right node and get less retry in
__alloc_pages_slowpath() because there is nothing to do.

Link: https://lkml.kernel.org/r/20240822092612.3209286-1-hezhongkun.hzk@bytedance.com
Signed-off-by: Zhongkun He <hezhongkun.hzk@bytedance.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03 21:15:47 -07:00
Yu Zhao
e98337d11b mm/contig_alloc: support __GFP_COMP
Patch series "mm/hugetlb: alloc/free gigantic folios", v2.

Use __GFP_COMP for gigantic folios can greatly reduce not only the amount
of code but also the allocation and free time.

Approximate LOC to mm/hugetlb.c: +60, -240

Allocate and free 500 1GB hugeTLB memory without HVO by:
  time echo 500 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
  time echo 0 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages

       Before  After
Alloc  ~13s    ~10s
Free   ~15s    <1s

The above magnitude generally holds for multiple x86 and arm64 CPU
models.

Perf profile before:
  Alloc
    - 99.99% alloc_pool_huge_folio
       - __alloc_fresh_hugetlb_folio
          - 83.23% alloc_contig_pages_noprof
             - 47.46% alloc_contig_range_noprof
                - 20.96% isolate_freepages_range
                     16.10% split_page
                - 14.10% start_isolate_page_range
                - 12.02% undo_isolate_page_range

  Free
    - update_and_free_pages_bulk
       - 87.71% free_contig_range
          - 76.02% free_unref_page
             - 41.30% free_unref_page_commit
                - 32.58% free_pcppages_bulk
                   - 24.75% __free_one_page
               13.96% _raw_spin_trylock
         12.27% __update_and_free_hugetlb_folio

Perf profile after:
  Alloc
    - 99.99% alloc_pool_huge_folio
         alloc_gigantic_folio
       - alloc_contig_pages_noprof
          - 59.15% alloc_contig_range_noprof
             - 20.72% start_isolate_page_range
               20.64% prep_new_page
             - 17.13% undo_isolate_page_range

  Free
    - update_and_free_pages_bulk
       - __folio_put
       - __free_pages_ok
            7.46% free_tail_page_prepare
          - 1.97% free_one_page
               1.86% __free_one_page

This patch (of 3):

Support __GFP_COMP in alloc_contig_range().  When the flag is set, upon
success the function returns a large folio prepared by prep_new_page(),
rather than a range of order-0 pages prepared by split_free_pages() (which
is renamed from split_map_pages()).

alloc_contig_range() can be used to allocate folios larger than
MAX_PAGE_ORDER, e.g., gigantic hugeTLB folios.  So on the free path,
free_one_page() needs to handle that by split_large_buddy().

[akpm@linux-foundation.org: fix folio_alloc_gigantic_noprof() WARN expression, per Yu Liao]
Link: https://lkml.kernel.org/r/20240814035451.773331-1-yuzhao@google.com
Link: https://lkml.kernel.org/r/20240814035451.773331-2-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Frank van der Linden <fvdl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03 21:15:36 -07:00
Kirill A. Shutemov
59149bf8ce mm: accept to promo watermark
Commit c574bbe917 ("NUMA balancing: optimize page placement for memory
tiering system") introduced a new watermark above "high" -- "promo".

Accept memory memory to the highest watermark which is WMARK_PROMO now.

Link: https://lkml.kernel.org/r/20240809114854.3745464-9-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:07 -07:00
Kirill A. Shutemov
55ad43e8ba mm: add a helper to accept page
Accept a given struct page and add it free list.

The help is useful for physical memory scanners that want to use free
unaccepted memory.

Link: https://lkml.kernel.org/r/20240809114854.3745464-7-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:07 -07:00
Kirill A. Shutemov
5adfeaecc4 mm: rework accept memory helpers
Make accept_memory() and range_contains_unaccepted_memory() take 'start'
and 'size' arguments instead of 'start' and 'end'.

Remove accept_page(), replacing it with direct calls to accept_memory(). 
The accept_page() name is going to be used for a different function.

Link: https://lkml.kernel.org/r/20240809114854.3745464-6-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:07 -07:00
Kirill A. Shutemov
310183de7b mm: introduce PageUnaccepted() page type
The new page type allows physical memory scanners to detect unaccepted
memory and handle it accordingly.

The page type is serialized with zone lock.

Link: https://lkml.kernel.org/r/20240809114854.3745464-5-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:06 -07:00
Kirill A. Shutemov
4be9064baa mm: accept memory in __alloc_pages_bulk()
Currently, the kernel only accepts memory in get_page_from_freelist(), but
there is another path that directly takes pages from free lists -
__alloc_page_bulk().  This function can consume all accepted memory and
will resort to __alloc_pages_noprof() if necessary.

Conditionally accepted in __alloc_pages_bulk().

The same issue may arise due to deferred page initialization.  Kick the
deferred initialization machinery before abandoning the zone, as the
kernel does in get_page_from_freelist().

Link: https://lkml.kernel.org/r/20240809114854.3745464-4-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:06 -07:00
Kirill A. Shutemov
3a80b8228f mm: reduce deferred struct page init ifdeffery
Patch series "mm: Fix several issues with unaccepted memory", v2.

The patchset addresses several issues related to unaccepted memory.

Pacth 1/7 preparatory cleanup.

Patch 2/7 ensures that __alloc_pages_bulk() will not exhaust all
accepted memory without accepting more.

Patches 3/7-5/7 are preparations for patch 6/7, which fixes
alloc_config_page() on machines with unaccepted memory.  This allows, for
example, the allocation of gigantic pages at runtime.

Patch 7/7 enables the kernel to accept memory up to the promo watermark.


This patch (of 7):

Add dummy _deferred_grow_zone() for !DEFERRED_STRUCT_PAGE_INIT and remove
#ifdefs in two places.

No functional changes.

Link: https://lkml.kernel.org/r/20240809114854.3745464-1-kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/20240809114854.3745464-3-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:06 -07:00
Wei Yang
29943248af mm: improve code consistency with zonelist_* helper functions
Replace direct access to zoneref->zone, zoneref->zone_idx, or
zone_to_nid(zoneref->zone) with the corresponding zonelist_* helper
functions for consistency.

No functional change.

Link: https://lkml.kernel.org/r/20240729091717.464-1-shivankg@amd.com
Co-developed-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:25:55 -07:00
Hao Ge
5e9784e997 codetag: debug: mark codetags for poisoned page as empty
When PG_hwpoison pages are freed they are treated differently in
free_pages_prepare() and instead of being released they are isolated.

Page allocation tag counters are decremented at this point since the page
is considered not in use.  Later on when such pages are released by
unpoison_memory(), the allocation tag counters will be decremented again
and the following warning gets reported:

[  113.930443][ T3282] ------------[ cut here ]------------
[  113.931105][ T3282] alloc_tag was not set
[  113.931576][ T3282] WARNING: CPU: 2 PID: 3282 at ./include/linux/alloc_tag.h:130 pgalloc_tag_sub.part.66+0x154/0x164
[  113.932866][ T3282] Modules linked in: hwpoison_inject fuse ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ebtable_nat ebtable_broute ip6table_nat ip6table_man4
[  113.941638][ T3282] CPU: 2 UID: 0 PID: 3282 Comm: madvise11 Kdump: loaded Tainted: G        W          6.11.0-rc4-dirty #18
[  113.943003][ T3282] Tainted: [W]=WARN
[  113.943453][ T3282] Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
[  113.944378][ T3282] pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  113.945319][ T3282] pc : pgalloc_tag_sub.part.66+0x154/0x164
[  113.946016][ T3282] lr : pgalloc_tag_sub.part.66+0x154/0x164
[  113.946706][ T3282] sp : ffff800087093a10
[  113.947197][ T3282] x29: ffff800087093a10 x28: ffff0000d7a9d400 x27: ffff80008249f0a0
[  113.948165][ T3282] x26: 0000000000000000 x25: ffff80008249f2b0 x24: 0000000000000000
[  113.949134][ T3282] x23: 0000000000000001 x22: 0000000000000001 x21: 0000000000000000
[  113.950597][ T3282] x20: ffff0000c08fcad8 x19: ffff80008251e000 x18: ffffffffffffffff
[  113.952207][ T3282] x17: 0000000000000000 x16: 0000000000000000 x15: ffff800081746210
[  113.953161][ T3282] x14: 0000000000000000 x13: 205d323832335420 x12: 5b5d353031313339
[  113.954120][ T3282] x11: ffff800087093500 x10: 000000000000005d x9 : 00000000ffffffd0
[  113.955078][ T3282] x8 : 7f7f7f7f7f7f7f7f x7 : ffff80008236ba90 x6 : c0000000ffff7fff
[  113.956036][ T3282] x5 : ffff000b34bf4dc8 x4 : ffff8000820aba90 x3 : 0000000000000001
[  113.956994][ T3282] x2 : ffff800ab320f000 x1 : 841d1e35ac932e00 x0 : 0000000000000000
[  113.957962][ T3282] Call trace:
[  113.958350][ T3282]  pgalloc_tag_sub.part.66+0x154/0x164
[  113.959000][ T3282]  pgalloc_tag_sub+0x14/0x1c
[  113.959539][ T3282]  free_unref_page+0xf4/0x4b8
[  113.960096][ T3282]  __folio_put+0xd4/0x120
[  113.960614][ T3282]  folio_put+0x24/0x50
[  113.961103][ T3282]  unpoison_memory+0x4f0/0x5b0
[  113.961678][ T3282]  hwpoison_unpoison+0x30/0x48 [hwpoison_inject]
[  113.962436][ T3282]  simple_attr_write_xsigned.isra.34+0xec/0x1cc
[  113.963183][ T3282]  simple_attr_write+0x38/0x48
[  113.963750][ T3282]  debugfs_attr_write+0x54/0x80
[  113.964330][ T3282]  full_proxy_write+0x68/0x98
[  113.964880][ T3282]  vfs_write+0xdc/0x4d0
[  113.965372][ T3282]  ksys_write+0x78/0x100
[  113.965875][ T3282]  __arm64_sys_write+0x24/0x30
[  113.966440][ T3282]  invoke_syscall+0x7c/0x104
[  113.966984][ T3282]  el0_svc_common.constprop.1+0x88/0x104
[  113.967652][ T3282]  do_el0_svc+0x2c/0x38
[  113.968893][ T3282]  el0_svc+0x3c/0x1b8
[  113.969379][ T3282]  el0t_64_sync_handler+0x98/0xbc
[  113.969980][ T3282]  el0t_64_sync+0x19c/0x1a0
[  113.970511][ T3282] ---[ end trace 0000000000000000 ]---

To fix this, clear the page tag reference after the page got isolated
and accounted for.

Link: https://lkml.kernel.org/r/20240825163649.33294-1-hao.ge@linux.dev
Fixes: d224eb0287 ("codetag: debug: mark codetags for reserved pages as empty")
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hao Ge <gehao@kylinos.cn>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: <stable@vger.kernel.org>	[6.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 17:59:02 -07:00
Suren Baghdasaryan
a8fc28dad6 alloc_tag: introduce clear_page_tag_ref() helper function
In several cases we are freeing pages which were not allocated using
common page allocators.  For such cases, in order to keep allocation
accounting correct, we should clear the page tag to indicate that the page
being freed is expected to not have a valid allocation tag.  Introduce
clear_page_tag_ref() helper function to be used for this.

Link: https://lkml.kernel.org/r/20240813150758.855881-1-surenb@google.com
Fixes: d224eb0287 ("codetag: debug: mark codetags for reserved pages as empty")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>	[6.10]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-15 22:16:16 -07:00
Kirill A. Shutemov
807174a93d mm: fix endless reclaim on machines with unaccepted memory
Unaccepted memory is considered unusable free memory, which is not counted
as free on the zone watermark check.  This causes get_page_from_freelist()
to accept more memory to hit the high watermark, but it creates problems
in the reclaim path.

The reclaim path encounters a failed zone watermark check and attempts to
reclaim memory.  This is usually successful, but if there is little or no
reclaimable memory, it can result in endless reclaim with little to no
progress.  This can occur early in the boot process, just after start of
the init process when the only reclaimable memory is the page cache of the
init executable and its libraries.

Make unaccepted memory free from watermark check point of view.  This way
unaccepted memory will never be the trigger of memory reclaim.  Accept
more memory in the get_page_from_freelist() if needed.

Link: https://lkml.kernel.org/r/20240809114854.3745464-2-kirill.shutemov@linux.intel.com
Fixes: dcdfdd40fa ("mm: Add support for unaccepted memory")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Jianxiong Gao <jxgao@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Jianxiong Gao <jxgao@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>	[6.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-15 22:16:15 -07:00
Pasha Tatashin
9d85731110 mm: don't account memmap per-node
Fix invalid access to pgdat during hot-remove operation:
ndctl users reported a GPF when trying to destroy a namespace:
$ ndctl destroy-namespace all -r all -f
 Segmentation fault
 dmesg:
 Oops: general protection fault, probably for
 non-canonical address 0xdffffc0000005650: 0000 [#1] PREEMPT SMP KASAN
 PTI
 KASAN: probably user-memory-access in range
 [0x000000000002b280-0x000000000002b287]
 CPU: 26 UID: 0 PID: 1868 Comm: ndctl Not tainted 6.11.0-rc1 #1
 Hardware name: Dell Inc. PowerEdge R640/08HT8T, BIOS
 2.20.1 09/13/2023
 RIP: 0010:mod_node_page_state+0x2a/0x110

cxl-test users report a GPF when trying to unload the test module:
$ modrpobe -r cxl-test
 dmesg
 BUG: unable to handle page fault for address: 0000000000004200
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 0 UID: 0 PID: 1076 Comm: modprobe Tainted: G O N 6.11.0-rc1 #197
 Tainted: [O]=OOT_MODULE, [N]=TEST
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/15
 RIP: 0010:mod_node_page_state+0x6/0x90

Currently, when memory is hot-plugged or hot-removed the accounting is
done based on the assumption that memmap is allocated from the same node
as the hot-plugged/hot-removed memory, which is not always the case.

In addition, there are challenges with keeping the node id of the memory
that is being remove to the time when memmap accounting is actually
performed: since this is done after remove_pfn_range_from_zone(), and
also after remove_memory_block_devices(). Meaning that we cannot use
pgdat nor walking though memblocks to get the nid.

Given all of that, account the memmap overhead system wide instead.

For this we are going to be using global atomic counters, but given that
memmap size is rarely modified, and normally is only modified either
during early boot when there is only one CPU, or under a hotplug global
mutex lock, therefore there is no need for per-cpu optimizations.

Also, while we are here rename nr_memmap to nr_memmap_pages, and
nr_memmap_boot to nr_memmap_boot_pages to be self explanatory that the
units are in page count.

[pasha.tatashin@soleen.com: address a few nits from David Hildenbrand]
  Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240808213437.682006-4-pasha.tatashin@soleen.com
Fixes: 15995a3524 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/linux-cxl/CAHj4cs9Ax1=CoJkgBGP_+sNu6-6=6v=_L-ZBZY0bVLD3wUWZQg@mail.gmail.com
Reported-by: Alison Schofield <alison.schofield@intel.com>
Closes: https://lore.kernel.org/linux-mm/Zq0tPd2h6alFz8XF@aschofie-mobl2/#t
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Fan Ni <fan.ni@samsung.com>
Cc: Joel Granados <j.granados@samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-15 22:16:14 -07:00
Qais Yousef
ae04f69de0 sched/rt: Rename realtime_{prio, task}() to rt_or_dl_{prio, task}()
Some find the name realtime overloaded. Use rt_or_dl() as an
alternative, hopefully better, name.

Suggested-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Qais Yousef <qyousef@layalina.io>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240610192018.1567075-4-qyousef@layalina.io
2024-08-07 18:32:38 +02:00
Qais Yousef
130fd056dd sched/rt: Clean up usage of rt_task()
rt_task() checks if a task has RT priority. But depends on your
dictionary, this could mean it belongs to RT class, or is a 'realtime'
task, which includes RT and DL classes.

Since this has caused some confusion already on discussion [1], it
seemed a clean up is due.

I define the usage of rt_task() to be tasks that belong to RT class.
Make sure that it returns true only for RT class and audit the users and
replace the ones required the old behavior with the new realtime_task()
which returns true for RT and DL classes. Introduce similar
realtime_prio() to create similar distinction to rt_prio() and update
the users that required the old behavior to use the new function.

Move MAX_DL_PRIO to prio.h so it can be used in the new definitions.

Document the functions to make it more obvious what is the difference
between them. PI-boosted tasks is a factor that must be taken into
account when choosing which function to use.

Rename task_is_realtime() to realtime_task_policy() as the old name is
confusing against the new realtime_task().

No functional changes were intended.

[1] https://lore.kernel.org/lkml/20240506100509.GL40213@noisy.programming.kicks-ass.net/

Signed-off-by: Qais Yousef <qyousef@layalina.io>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240610192018.1567075-2-qyousef@layalina.io
2024-08-07 18:32:37 +02:00
Li Zhijian
66eca1021a mm/page_alloc: fix pcp->count race between drain_pages_zone() vs __rmqueue_pcplist()
It's expected that no page should be left in pcp_list after calling
zone_pcp_disable() in offline_pages().  Previously, it's observed that
offline_pages() gets stuck [1] due to some pages remaining in pcp_list.

Cause:
There is a race condition between drain_pages_zone() and __rmqueue_pcplist()
involving the pcp->count variable. See below scenario:

         CPU0                              CPU1
    ----------------                    ---------------
                                      spin_lock(&pcp->lock);
                                      __rmqueue_pcplist() {
zone_pcp_disable() {
                                        /* list is empty */
                                        if (list_empty(list)) {
                                          /* add pages to pcp_list */
                                          alloced = rmqueue_bulk()
  mutex_lock(&pcp_batch_high_lock)
  ...
  __drain_all_pages() {
    drain_pages_zone() {
      /* read pcp->count, it's 0 here */
      count = READ_ONCE(pcp->count)
      /* 0 means nothing to drain */
                                          /* update pcp->count */
                                          pcp->count += alloced << order;
      ...
                                      ...
                                      spin_unlock(&pcp->lock);

In this case, after calling zone_pcp_disable() though, there are still some
pages in pcp_list. And these pages in pcp_list are neither movable nor
isolated, offline_pages() gets stuck as a result.

Solution:
Expand the scope of the pcp->lock to also protect pcp->count in
drain_pages_zone(), to ensure no pages are left in the pcp list after
zone_pcp_disable()

[1] https://lore.kernel.org/linux-mm/6a07125f-e720-404c-b2f9-e55f3f166e85@fujitsu.com/

Link: https://lkml.kernel.org/r/20240723064428.1179519-1-lizhijian@fujitsu.com
Fixes: 4b23a68f95 ("mm/page_alloc: protect PCP lists with a spinlock")
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Reported-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-26 14:33:09 -07:00
Suren Baghdasaryan
b3bebe4430 alloc_tag: outline and export free_reserved_page()
Outline and export free_reserved_page() because modules use it and it in
turn uses page_ext_{get|put} which should not be exported.  The same
result could be obtained by outlining {get|put}_page_tag_ref() but that
would have higher performance impact as these functions are used in more
performance critical paths.

Link: https://lkml.kernel.org/r/20240717212844.2749975-1-surenb@google.com
Fixes: dcfe378c81 ("lib: introduce support for page allocation tagging")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202407080044.DWMC9N9I-lkp@intel.com/
Suggested-by: Christoph Hellwig <hch@infradead.org>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: <stable@vger.kernel.org>	[6.10]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-26 14:33:09 -07:00
Joel Granados
78eb4ea25c sysctl: treewide: constify the ctl_table argument of proc_handlers
const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
  virtual patch

  @r1@
  identifier ctl, write, buffer, lenp, ppos;
  identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

  @r2@
  identifier func, ctl, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos)
  { ... }

  @r3@
  identifier func;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int , void *, size_t *, loff_t *);

  @r4@
  identifier func, ctl;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int , void *, size_t *, loff_t *);

  @r5@
  identifier func, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
  conventions. The xfs_stats_clear_proc_handler,
  xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
  adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
  This is called from a proc_handler itself and is calling back into
  another proc_handler, making it necessary to change it as part of the
  proc_handler migration.

Co-developed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Co-developed-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Joel Granados <j.granados@samsung.com>
2024-07-24 20:59:29 +02:00
Vlastimil Babka
53dabce265 mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC
This mostly reverts commit af3b854492 ("mm/page_alloc.c: allow error
injection").  The commit made should_fail_alloc_page() a noinline function
that's always called from the page allocation hotpath, even if it's empty
because CONFIG_FAIL_PAGE_ALLOC is not enabled, and there is no option to
disable it and prevent the associated function call overhead.

As with the preceding patch "mm, slab: put should_failslab back behind
CONFIG_SHOULD_FAILSLAB" and for the same reasons, put the
should_fail_alloc_page() back behind the config option.  When enabled, the
ALLOW_ERROR_INJECTION and BTF_ID records are preserved so it's not a
complete revert.

Link: https://lkml.kernel.org/r/20240711-b4-fault-injection-reverts-v1-2-9e2651945d68@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-17 21:05:18 -07:00
Wei Yang
f6953e22af mm/page_alloc: put __free_pages_core() in __meminit section
__free_pages_core() is only used in bootmem init and hot-add memory init
path.  Let's put it in __meminit section.

Link: https://lkml.kernel.org/r/20240706061615.30322-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12 15:52:21 -07:00
Wei Yang
689d92cc81 mm/page_alloc: remove prefetchw() on freeing page to buddy system
The prefetchw() is introduced from an ancient patch[1].

The change log says:

    The basic idea is to free higher order pages instead of going
    through every single one.  Also, some unnecessary atomic operations
    are done away with and replaced with non-atomic equivalents, and
    prefetching is done where it helps the most.  For a more in-depth
    discusion of this patch, please see the linux-ia64 archives (topic
    is "free bootmem feedback patch").

So there are several changes improve the bootmem freeing, in which the
most basic idea is freeing higher order pages.  And as Matthew says,
"Itanium CPUs of this era had no prefetchers."

I did 10 round bootup tests before and after this change, the data doesn't
prove prefetchw() help speeding up bootmem freeing.  The sum of the 10
round bootmem freeing time after prefetchw() removal even 5.2% faster than
before.

[1]: https://lore.kernel.org/linux-ia64/40F46962.4090604@sgi.com/

Link: https://lkml.kernel.org/r/20240702020931.7061-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-10 12:14:54 -07:00
Kefeng Wang
593a10dabe mm: refactor folio_undo_large_rmappable()
Folios of order <= 1 are not in deferred list, the check of order is added
into folio_undo_large_rmappable() from commit 8897277acf ("mm: support
order-1 folios in the page cache"), but there is a repeated check for
small folio (order 0) during each call of the
folio_undo_large_rmappable(), so only keep folio_order() check inside the
function.

In addition, move all the checks into header file to save a function call
for non-large-rmappable or empty deferred_list folio.

Link: https://lkml.kernel.org/r/20240521130315.46072-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-04 18:05:50 -07:00
Wei Yang
08af2c12e3 mm/page_alloc: reword the comment of buddy_merge_likely()
For page with order O, we are checking its order (O + 1)'s buddy.  If it
is free, we would like to put it to the tail and expect it would be merged
to a page with order (O + 2).

Reword the comment to reflect it.

Link: https://lkml.kernel.org/r/20240619010612.20740-4-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:19 -07:00
Wei Yang
b719efa22d mm/page_alloc: fix a typo in comment about GFP flag
The GFP flags used to choose the zonelist is __GFP_THISNODE.

Let's change it to what exactly it should be.

Link: https://lkml.kernel.org/r/20240619010612.20740-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:19 -07:00
David Hildenbrand
5062574422 mm/memory_hotplug: skip adjust_managed_page_count() for PageOffline() pages when offlining
We currently have a hack for virtio-mem in place to handle memory
offlining with PageOffline pages for which we already adjusted the managed
page count.

Let's enlighten memory offlining code so we can get rid of that hack, and
document the situation.

Link: https://lkml.kernel.org/r/20240607090939.89524-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Marco Elver <elver@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:18 -07:00
David Hildenbrand
503b158fc3 mm/memory_hotplug: initialize memmap of !ZONE_DEVICE with PageOffline() instead of PageReserved()
We currently initialize the memmap such that PG_reserved is set and the
refcount of the page is 1.  In virtio-mem code, we have to manually clear
that PG_reserved flag to make memory offlining with partially hotplugged
memory blocks possible: has_unmovable_pages() would otherwise bail out on
such pages.

We want to avoid PG_reserved where possible and move to typed pages
instead.  Further, we want to further enlighten memory offlining code
about PG_offline: offline pages in an online memory section.  One example
is handling managed page count adjustments in a cleaner way during memory
offlining.

So let's initialize the pages with PG_offline instead of PG_reserved. 
generic_online_page()->__free_pages_core() will now clear that flag before
handing that memory to the buddy.

Note that the page refcount is still 1 and would forbid offlining of such
memory except when special care is take during GOING_OFFLINE as currently
only implemented by virtio-mem.

With this change, we can now get non-PageReserved() pages in the XEN
balloon list.  From what I can tell, that can already happen via
decrease_reservation(), so that should be fine.

HV-balloon should not really observe a change: partial online memory
blocks still cannot get surprise-offlined, because the refcount of these
PageOffline() pages is 1.

Update virtio-mem, HV-balloon and XEN-balloon code to be aware that
hotplugged pages are now PageOffline() instead of PageReserved() before
they are handed over to the buddy.

We'll leave the ZONE_DEVICE case alone for now.

Note that self-hosted vmemmap pages will no longer be marked as
reserved.  This matches ordinary vmemmap pages allocated from the buddy
during memory hotplug.  Now, really only vmemmap pages allocated from
memblock during early boot will be marked reserved.  Existing
PageReserved() checks seem to be handling all relevant cases correctly
even after this change.

Link: https://lkml.kernel.org/r/20240607090939.89524-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de> [generic memory-hotplug bits]
Cc: Alexander Potapenko <glider@google.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Marco Elver <elver@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:18 -07:00
David Hildenbrand
13c526540b mm: pass meminit_context to __free_pages_core()
Patch series "mm/memory_hotplug: use PageOffline() instead of
PageReserved() for !ZONE_DEVICE".

This can be a considered a long-overdue follow-up to some parts of [1]. 
The patches are based on [2], but they are not strictly required -- just
makes it clearer why we can use adjust_managed_page_count() for memory
hotplug without going into details about highmem.

We stop initializing pages with PageReserved() in memory hotplug code --
except when dealing with ZONE_DEVICE for now.  Instead, we use
PageOffline(): all pages are initialized to PageOffline() when onlining a
memory section, and only the ones actually getting exposed to the
system/page allocator will get PageOffline cleared.

This way, we enlighten memory hotplug more about PageOffline() pages and
can cleanup some hacks we have in virtio-mem code.

What about ZONE_DEVICE?  PageOffline() is wrong, but we might just stop
using PageReserved() for them later by simply checking for
is_zone_device_page() at suitable places.  That will be a separate patch
set / proposal.

This primarily affects virtio-mem, HV-balloon and XEN balloon. I only
briefly tested with virtio-mem, which benefits most from these cleanups.

[1] https://lore.kernel.org/all/20191024120938.11237-1-david@redhat.com/
[2] https://lkml.kernel.org/r/20240607083711.62833-1-david@redhat.com


This patch (of 3):

In preparation for further changes, let's teach __free_pages_core() about
the differences of memory hotplug handling.

Move the memory hotplug specific handling from generic_online_page() to
__free_pages_core(), use adjust_managed_page_count() on the memory hotplug
path, and spell out why memory freed via memblock cannot currently use
adjust_managed_page_count().

[david@redhat.com: add missed CONFIG_DEFERRED_STRUCT_PAGE_INIT]
  Link: https://lkml.kernel.org/r/b72e6efd-fb0a-459c-b1a0-88a98e5b19e2@redhat.com
[david@redhat.com: fix up the memblock comment, per Oscar]
  Link: https://lkml.kernel.org/r/2ed64218-7f3b-4302-a5dc-27f060654fe2@redhat.com
[david@redhat.com: add the parameter name also in the declaration]
  Link: https://lkml.kernel.org/r/ca575956-f0dd-4fb9-a307-6b7621681ed9@redhat.com
Link: https://lkml.kernel.org/r/20240607090939.89524-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240607090939.89524-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Marco Elver <elver@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:18 -07:00
David Hildenbrand
e4d970acfb mm/page_alloc: clear PageBuddy using __ClearPageBuddy() for bad pages
Let's stop using page_mapcount_reset() and clear PageBuddy using
__ClearPageBuddy() instead.

Link: https://lkml.kernel.org/r/20240529111904.2069608-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org>	[zram/zsmalloc workloads]
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:17 -07:00
Sourav Panda
15995a3524 mm: report per-page metadata information
Today, we do not have any observability of per-page metadata and how much
it takes away from the machine capacity.  Thus, we want to describe the
amount of memory that is going towards per-page metadata, which can vary
depending on build configuration, machine architecture, and system use.

This patch adds 2 fields to /proc/vmstat that can used as shown below:

Accounting per-page metadata allocated by boot-allocator:
	/proc/vmstat:nr_memmap_boot * PAGE_SIZE

Accounting per-page metadata allocated by buddy-allocator:
	/proc/vmstat:nr_memmap * PAGE_SIZE

Accounting total Perpage metadata allocated on the machine:
	(/proc/vmstat:nr_memmap_boot +
	 /proc/vmstat:nr_memmap) * PAGE_SIZE

Utility for userspace:

Observability: Describe the amount of memory overhead that is going to
per-page metadata on the system at any given time since this overhead is
not currently observable.

Debugging: Tracking the changes or absolute value in struct pages can help
detect anomalies as they can be correlated with other metrics in the
machine (e.g., memtotal, number of huge pages, etc).

page_ext overheads: Some kernel features such as page_owner
page_table_check that use page_ext can be optionally enabled via kernel
parameters.  Having the total per-page metadata information helps users
precisely measure impact.  Furthermore, page-metadata metrics will reflect
the amount of struct pages reliquished (or overhead reduced) when
hugetlbfs pages are reserved which will vary depending on whether hugetlb
vmemmap optimization is enabled or not.

For background and results see:
lore.kernel.org/all/20240220214558.3377482-1-souravpanda@google.com

Link: https://lkml.kernel.org/r/20240605222751.1406125-1-souravpanda@google.com
Signed-off-by: Sourav Panda <souravpanda@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chen Linxuan <chenlinxuan@uniontech.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tomas Mudrunka <tomas.mudrunka@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:09 -07:00
David Hildenbrand
7a581204b1 mm/highmem: reimplement totalhigh_pages() by walking zones
Patch series "mm/highmem: don't track highmem pages manually".

Let's remove highmem special-casing from adjust_managed_page_count(), to
result in less confusion why memblock manually adjusts totalram_pages, and
__free_pages_core() only adjusts the zone's managed pages -- what about
the highmem pages that adjust_managed_page_count() updates?

Now, we only maintain totalram_pages and a zone's managed pages
independent of highmem support.  We can derive the number of highmem pages
simply by looking at the relevant zone's managed pages.  I don't think
there is any particular fast path that needs a maximum-efficient
totalhigh_pages() implementation.

Note that highmem memory is currently initialized using
free_highmem_page()->free_reserved_page(), not __free_pages_core().  In
the future we might want to also use __free_pages_core() to initialize
highmem memory, to make that less special, and consider moving
totalram_pages updates into __free_pages_core() [1], so we can just use
adjust_managed_page_count() in there as well.

Booting a simple kernel in QEMU reveals no highmem accounting change:

Before:
  Memory: 3095448K/3145208K available (14802K kernel code, 2073K rwdata,
  5000K rodata, 740K init, 556K bss, 49760K reserved, 0K cma-reserved,
  2244488K highmem)

After:
  Memory: 3095276K/3145208K available (14802K kernel code, 2073K rwdata,
  5000K rodata, 740K init, 556K bss, 49932K reserved, 0K cma-reserved,
  2244488K highmem)

[1] https://lkml.kernel.org/r/20240601133402.2675-1-richard.weiyang@gmail.com


This patch (of 2):

Can we get rid of the highmem ifdef in adjust_managed_page_count()? 
Likely yes: we don't have that many totalhigh_pages() users, and they all
don't seem to be very performance critical.

So let's implement totalhigh_pages() like nr_free_highpages(), collecting
information from all zones.  This is now similar to what we do in
si_meminfo_node() to collect the per-node highmem page count.

In the common case (single node, 3-4 zones), we really shouldn't care.  We
could optimize a bit further (only walk ZONE_HIGHMEM and ZONE_MOVABLE if
required), but there doesn't seem a real need for that.

[david@redhat.com: fix build bot complaint]
  Link: https://lkml.kernel.org/r/b57e5bc4-eb72-40e3-add4-57dfa6e03df6@redhat.com
Link: https://lkml.kernel.org/r/20240607083711.62833-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240607083711.62833-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:06 -07:00
yangge
bf14ed81f5 mm/page_alloc: Separate THP PCP into movable and non-movable categories
Since commit 5d0a661d80 ("mm/page_alloc: use only one PCP list for
THP-sized allocations") no longer differentiates the migration type of
pages in THP-sized PCP list, it's possible that non-movable allocation
requests may get a CMA page from the list, in some cases, it's not
acceptable.

If a large number of CMA memory are configured in system (for example, the
CMA memory accounts for 50% of the system memory), starting a virtual
machine with device passthrough will get stuck.  During starting the
virtual machine, it will call pin_user_pages_remote(..., FOLL_LONGTERM,
...) to pin memory.  Normally if a page is present and in CMA area,
pin_user_pages_remote() will migrate the page from CMA area to non-CMA
area because of FOLL_LONGTERM flag.  But if non-movable allocation
requests return CMA memory, migrate_longterm_unpinnable_pages() will
migrate a CMA page to another CMA page, which will fail to pass the check
in check_and_migrate_movable_pages() and cause migration endless.

Call trace:
pin_user_pages_remote
--__gup_longterm_locked // endless loops in this function
----_get_user_pages_locked
----check_and_migrate_movable_pages
------migrate_longterm_unpinnable_pages
--------alloc_migration_target

This problem will also have a negative impact on CMA itself.  For example,
when CMA is borrowed by THP, and we need to reclaim it through cma_alloc()
or dma_alloc_coherent(), we must move those pages out to ensure CMA's
users can retrieve that contigous memory.  Currently, CMA's memory is
occupied by non-movable pages, meaning we can't relocate them.  As a
result, cma_alloc() is more likely to fail.

To fix the problem above, we add one PCP list for THP, which will not
introduce a new cacheline for struct per_cpu_pages.  THP will have 2 PCP
lists, one PCP list is used by MOVABLE allocation, and the other PCP list
is used by UNMOVABLE allocation.  MOVABLE allocation contains GPF_MOVABLE,
and UNMOVABLE allocation contains GFP_UNMOVABLE and GFP_RECLAIMABLE.

Link: https://lkml.kernel.org/r/1718845190-4456-1-git-send-email-yangge1116@126.com
Fixes: 5d0a661d80 ("mm/page_alloc: use only one PCP list for THP-sized allocations")
Signed-off-by: yangge <yangge1116@126.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:11 -07:00
David Hildenbrand
384a746bb5 Revert "mm: init_mlocked_on_free_v3"
There was insufficient review and no agreement that this is the right
approach.

There are serious flaws with the implementation that make processes using
mlock() not even work with simple fork() [1] and we get reliable crashes
when rebooting.

Further, simply because we might be unmapping a single PTE of a large
mlocked folio, we shouldn't zero out the whole folio.

... especially because the code can also *corrupt* urelated memory because
	kernel_init_pages(page, folio_nr_pages(folio));

Could end up writing outside of the actual folio if we work with a tail
page.

Let's revert it.  Once there is agreement that this is the right approach,
the issues were fixed and there was reasonable review and proper testing,
we can consider it again.

[1] https://lkml.kernel.org/r/4da9da2f-73e4-45fd-b62f-a8a513314057@redhat.com

Link: https://lkml.kernel.org/r/20240605091710.38961-1-david@redhat.com
Fixes: ba42b524a0 ("mm: init_mlocked_on_free_v3")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: David Wang <00107082@163.com>
Closes: https://lore.kernel.org/lkml/20240528151340.4282-1-00107082@163.com/
Reported-by: Lance Yang <ioworker0@gmail.com>
Closes: https://lkml.kernel.org/r/20240601140917.43562-1-ioworker0@gmail.com
Acked-by: Lance Yang <ioworker0@gmail.com>
Cc: York Jasper Niebuhr <yjnworkstation@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-15 10:43:05 -07:00
Johannes Weiner
7cc5a5d650 mm: page_alloc: fix highatomic typing in multi-block buddies
Christoph reports a page allocator splat triggered by xfstests:

generic/176 214s ... [ 1204.507931] run fstests generic/176 at 2024-05-27 12:52:30
XFS (nvme0n1): Mounting V5 Filesystem cd936307-415f-48a3-b99d-a2d52ae1f273
XFS (nvme0n1): Ending clean mount
XFS (nvme1n1): Mounting V5 Filesystem ab3ee1a4-af62-4934-9a6a-6c2fde321850
XFS (nvme1n1): Ending clean mount
XFS (nvme1n1): Unmounting Filesystem ab3ee1a4-af62-4934-9a6a-6c2fde321850
XFS (nvme1n1): Mounting V5 Filesystem 7099b02d-9c58-4d1d-be1d-2cc472d12cd9
XFS (nvme1n1): Ending clean mount
------------[ cut here ]------------
page type is 3, passed migratetype is 1 (nr=512)
WARNING: CPU: 0 PID: 509870 at mm/page_alloc.c:645 expand+0x1c5/0x1f0
Modules linked in: i2c_i801 crc32_pclmul i2c_smbus [last unloaded: scsi_debug]
CPU: 0 PID: 509870 Comm: xfs_io Not tainted 6.10.0-rc1+ #2437
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:expand+0x1c5/0x1f0
Code: 05 16 70 bf 02 01 e8 ca fc ff ff 8b 54 24 34 44 89 e1 48 c7 c7 80 a2 28 83 48 89 c6 b8 01 00 3
RSP: 0018:ffffc90003b2b968 EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffffffff83fa9480 RCX: 0000000000000000
RDX: 0000000000000005 RSI: 0000000000000027 RDI: 00000000ffffffff
RBP: 00000000001f2600 R08: 00000000fffeffff R09: 0000000000000001
R10: 0000000000000000 R11: ffffffff83676200 R12: 0000000000000009
R13: 0000000000000200 R14: 0000000000000001 R15: ffffea0007c98000
FS:  00007f72ca3d5780(0000) GS:ffff8881f9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f72ca1fff38 CR3: 00000001aa0c6002 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 <TASK>
 ? __warn+0x7b/0x120
 ? expand+0x1c5/0x1f0
 ? report_bug+0x191/0x1c0
 ? handle_bug+0x3c/0x80
 ? exc_invalid_op+0x17/0x70
 ? asm_exc_invalid_op+0x1a/0x20
 ? expand+0x1c5/0x1f0
 ? expand+0x1c5/0x1f0
 __rmqueue_pcplist+0x3a9/0x730
 get_page_from_freelist+0x7a0/0xf00
 __alloc_pages_noprof+0x153/0x2e0
 __folio_alloc_noprof+0x10/0xa0
 __filemap_get_folio+0x16b/0x370
 iomap_write_begin+0x496/0x680

While trying to service a movable allocation (page type 1), the page
allocator runs into a two-pageblock buddy on the movable freelist whose
second block is typed as highatomic (page type 3).

This inconsistency is caused by the highatomic reservation system
operating on single pageblocks, while MAX_ORDER can be bigger than that -
in this configuration, pageblock_order is 9 while MAX_PAGE_ORDER is 10. 
The test case is observed to make several adjacent order-3 requests with
__GFP_DIRECT_RECLAIM cleared, which marks the surrounding block as
highatomic.  Upon freeing, the blocks merge into an order-10 buddy.  When
the highatomic pool is drained later on, this order-10 buddy gets moved
back to the movable list, but only the first pageblock is marked movable
again.  A subsequent expand() of this buddy warns about the tail being of
a different type.

This is a long-standing bug that's surfaced by the recent block type
warnings added to the allocator.  The consequences seem mostly benign, it
just results in odd behavior: the highatomic tail blocks are not properly
drained, instead they end up on the movable list first, then go back to
the highatomic list after an alloc-free cycle.

To fix this, make the highatomic reservation code aware that
allocations/buddies can be larger than a pageblock.

While it's an old quirk, the recently added type consistency warnings seem
to be the most prominent consequence of it.  Set the Fixes: tag
accordingly to highlight this backporting dependency.

Link: https://lkml.kernel.org/r/20240530114203.GA1222079@cmpxchg.org
Fixes: e0932b6c1f ("mm: page_alloc: consolidate free page accounting")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Christoph Hellwig <hch@lst.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-05 19:19:25 -07:00
Baolin Wang
231f8c7127 mm: page_alloc: allowing mTHP compaction to capture the freed page directly
Currently, compaction_capture() does not allow lower-order allocations to
directly capture the movable free pages, even though lower-order
allocations might also be requesting movable pages, that can lead to more
compaction scanning.  And, with the enablement of mTHP, such situations
will become more common.

Thus allowing lower-order (mTHP) allocations of movable page types
directly capture the movable free pages can avoid unnecessary compaction
scanning, meanwhile that won't pollute the movable pageblock.  With
testing 1M mTHP compaction, it can be seen that compaction scanning is
significantly reduced.

                                   mm-unstable       patched
Ops Compaction pages isolated      116598741.00   120946702.00
Ops Compaction migrate scanned    1764870054.00  1488621550.00
Ops Compaction free scanned       7707879039.00  4986299318.00
Ops Compact scan efficiency               22.90          29.85
Ops Compaction cost                    73797.69       72933.48

Link: https://lkml.kernel.org/r/8118a5d66a034736a48433beddaca60ed78577c4.1712892329.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:53:37 -07:00
David Hildenbrand
7115936ac1 mm/page_alloc: use folio_mapped() in __alloc_contig_migrate_range()
We want to limit the use of page_mapcount() to the places where it is
absolutely necessary.

For tracing purposes, we use page_mapcount() in
__alloc_contig_migrate_range().  Adding that mapcount to total_mapped
sounds strange: total_migrated and total_reclaimed would count each page
only once, not multiple times.

But then, isolate_migratepages_range() adds each folio only once to the
list.  So for large folios, we would query the mapcount of the first page
of the folio, which doesn't make too much sense for large folios.

Let's simply use folio_mapped() * folio_nr_pages(), which makes more sense
as nr_migratepages is also incremented by the number of pages in the folio
in case of successful migration.

Link: https://lkml.kernel.org/r/20240409192301.907377-11-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:53:30 -07:00